Cells are considered the fundamental units of life
All living organisms are made up of one or more cells
Unicellular organisms, like amoebas, consist of only a single cell
Multicellular organisms, like people, are made up of many cells
The cells in complex multicellular organisms like people are organized into tissues, groups of similar cells that work together on a specific task
Organs are structures made up of two or more tissues organized to carry out a particular function, and groups of organs with related functions make up the different organ systems
Hence the benefit of multicellular organisms that is not shared by single-celled organisms is populations of cells in a multicellular body can be specialized for specific functions
